The invention pertains to a hose band clip of the type having a turnbuckle and a tightening strap, the turnbuckle having a tightening worm which cooperates in openings in the strap in order to adjust same by rotation of the worm.
In such hose band clips, rotation of the worm can exert very large forces on the housing of the turnbuckle when the tightening strap is tightened. As a result, a danger of overloading arises which may lead to, for example, bending of the turnbuckle housing, which would jeopardize operating safety.
It is, therefore, a principle object of the invention to use a simple means of construction, which gives rise, if at all possible, to no additional costs, in order to ensure that the user of the hose band clip can, without employing torque-indicating wrenches, determine when the hose band clip is tightened with its planned, maximum permissible tension force.
This object is achieved, in accordance with a preferred embodiment, by using a hose band clip of the type initially noted, and providing narrow openings in longitudinal sidewalls of the housing of the turnbuckle which provide an optical indication that the tension force is not to be further increased. In particular, this optical indication is produced by deformation of the opening due to tension force transmitted by the worm.
The deformation of the narrow openings in the longitudinal sidewalls of the housing, which preferably is plastic deformation, but, if necessary, may also be elastic deformation, indicates when the tension force is sufficiently high and should not be increased any further in order to avoid overloading the turnbuckle or the tightening strap. The tension force which leads to visually detectable deformation of the narrow openings can always be set by selecting the thickness of the longitudinal sidewalls of the housing, the arrangement of the narrow openings and their height and also by the selection of material for the housing longitudinal sidewalls, in such a way that, when the maximum desired tension force which should not be exceeded is reached, the narrow openings are deformed to an extent visible to the naked eye for indicating that the tightening strap should not be stretched any further.
The narrow openings can be made in the longitudinal walls of the housing at no additional cost. If, as in the preferred arrangement, the housing of the turnbuckle is manufactured of sheet metal by punching and bending, these narrow openings can be punched out at the same time. If the housing is manufactured of die cast metal or injection molded plastic, these narrow openings can be formed in the housing at the same time as the manufacturing is done.
In the case of turnbuckles of particularly simple design, the worm can be placed at offsets in the housing longitudinal sidewalls and/or the housing cover, with these offsets being integral parts of the housing longitudinal sidewalls; in this case, it need only be ensured that the worm can transmit to the longitudinal sidewalls pressure forces which are large enough to deform the openings. For example, a neck of the worm which connects the head of the worm to the worm drive can be arranged in a connecting link which connects the two longitudinal sidewalls at their forward ends, and in this case, the openings which serve as an optical indication of the maximum planned tension force can be shaped as narrow, vertical windows, which are arranged near this connecting bridge in such a way that they extend over preferably at least the height of this link.
In a preferred embodiment, it is to be ensured that the turnbuckle features a cover which pivots the worm; this cover is to be mounted on the turnbuckle housing in such a way that it can move longitudinally, and features tabs which project to the sides, and which extend into recesses in the longitudinal sides of the housing, that the rear vertical sides of these recesses form abutments for the two tabs of the cover, and that in the longitudinal sidewalls of the housing are the openings which are slightly behind the rear vertical sides of the recesses. This makes it possible to restrict, within narrower limits, the tension force which leads to deformation of the holes. In this case, it is possible to ensure the longitudinal moveability of the cover on the housing in different ways. For example, at each of its longitudinal sides, the cover can feature one or more tabs which project to the side, and which extend into longitudinal holes in the housing sidewalls to mount the cover in such a way that it can move longitudinally. It is also possible to design the cover as a swivelling cover, so that the turnbuckle forms a quick-acting turnbuckle.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.